- Implement JupyterNotebookSecurity module with validation and sanitization
- Add content validation for dangerous code patterns, imports, and commands
- Implement read-only mode for untrusted notebooks
- Add configurable security settings with trusted sources support
- Provide cell-level sanitization and warning system
- Add comprehensive security tests (590 test cases)
- Update handlers and strategies to use security features
- Add detailed security documentation
This addresses the security concerns raised by @adamhill about arbitrary code execution risks in Jupyter notebooks.